The original version is available through Royal Society of Chemistry at DOI: 10.1039/c004660d

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dc.description.abstract

Controlling oxygen concentration at a microscale level can benefit experimental investigations involving oxidative stress, ischemia, and reactive oxygen species (ROS) mediated cellular pathways. Here, we report the application of microfluidic gradient generation in an open-well culture model, in
which a gradient of gas is delivered via diffusion through a gas permeable substrate that separates cells from the gas microchannels below. By using diffusion to localize oxygen delivery, microgradients of
oxygen concentrations can be rapidly and controllably applied without exposing cells to mechanical stresses or reducing culture volumes inside microfluidic culture chambers. Furthermore, we demonstrate the modulation of intracellular ROS levels in Madin–Darby Canine Kidney (MDCK) cells by applying these oxygen microgradients. Increases in ROS levels consistent with both oxidative
stress and hypoxic exposures were observed in MDCK cells. The measured ROS increases were
comparable to 100 mMhydrogen peroxide exposure in a control comparison, which is within the range of standard ROS induction methods. Incubation with 200 mM vitamin C was able to demodulate the ROS response at both hypoxic and hyperoxic exposures. By providing microfluidic controlled gradients, constant ROS exposure, and a shear-free open well design, the devices introduced here greatly improve upon standard oxygen-based culturing methods.

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dc.description.sponsorship

This work was supported by the Multidisciplinary Oral Sciences
Training Program, National Institutes of Health Grant T32 DE018381-01 and NSF 0852416.

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dc.language.iso

en_US

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dc.publisher

Royal Society of Chemistry

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dc.title

Oxygen gradients for open well cellular cultures via microfluidic substrates